Backgrounder on Russian Fuel Air Explosives ("Vacuum Bombs")

On December 27, 1999, Interfax reported Russian forces were using fuel-air explosive bombs in the fighting in Chechnya.(1) The use of fuel-air explosives (FAEs), popularly known in Russia as "vacuum bombs," represents a dangerous escalation in the Chechnya conflict--one with important humanitarian implications. FAEs are more powerful than conventional high-explosive munitions of comparable size, are more likely to kill and injure people in bunkers, shelters, and caves, and kill and injure in a particularly brutal manner over a wide area. In urban settings it is very difficult to limit the effect of this weapon to combatants, and the nature of FAE explosions makes it virtually impossible for civilians to take shelter from their destructive effect.

According to one Russian military scientist writing for the Russian military magazine Voyennyye Znaniya (Military Knowledge), FAE weapons are effective against exposed personnel, combat equipment, fortified areas and individual defensive fortifications, clearing passages in minefields, clearing landing sites for helicopters, destroying communication centers, and neutralizing strongholds in house-to-house fighting in a city.(2) In addition, he stated that "fuel-air explosives are capable...of completely destroying in a given area vegetation and agricultural crops that have been planted." "In its destructive capability, it is comparable to low-yield nuclear munitions."(3)

Used in large numbers, fuel-air explosives and other blast weapons can have enormous destructive effects. When multiple FAE warheads are exploded, the different blast waves reinforce each other, increasing their destructive power.(4) The effect of blast weapons is also compounded in buildings and other enclosed spaces, and is twelve to sixteen times more destructive than conventional high explosives against targets with large surface areas, such as frame buildings, bunkers, and vehicle shelters.(5)

Because FAEs cover a wide area, they are prone to indiscriminate use, especially in or near populated areas. Since this weapon is very effective against personnel in fortifications, bunkers, and other buildings, Russian forces may be tempted to use them in towns and cities where Chechen fighters are dug in. In urban settings it will be impossible for the Russians military to limit the destructive effect of this weapon to combatants and very difficult for civilians to take shelter from the FAE's effect.

So far, the Russian military has reportedly used FAE bombs against the Dagestani village of Tando, in August 1999,(6)and more recently in the southern mountains of Chechnya.(7)

How FAEs Work

A typical fuel air explosive device consists of a container of fuel and two separate explosive charges. After the munition is dropped or fired, the first explosive charge bursts open the container at a predetermined height and disperses the fuel in a cloud that mixes with atmospheric oxygen (the size of the cloud varies with the size of the munition). The cloud of fuel flows around objects and into structures. The second charge then detonates the cloud, creating a massive blast wave. (For a demonstration of a FAE explosion, see the U.S. Naval Air Warfare Center Weapons Division, China Lake, California, page at "http://www.nawcwpns.navy.mil/clmf/faeseq.html".) The blast wave destroys unreinforced buildings and equipment and kills and injures personnel. The antipersonnel effect of the blast wave is more severe in foxholes, on personnel with body armor, and in enclosed spaces such as caves, buildings, and bunkers.

Fuel-air explosives were first developed, and used in Vietnam, by the United States. Soviet scientists, however, quickly developed their own FAE weapons, which were reportedly used against China in a 1969 border conflict and in Afghanistan. Since then research and development has continued and currently Russian forces field a wide array of third-generation FAE warheads.

In addition to classic FAE munitions, Soviet scientists have also developed other "enhanced-blast" munitions, particularly reactive-surround and slurry-explosive blast warheads. Both types of warheads work on the same principle by which the explosive is dispersed and mixed with atmospheric oxygen before the detonation process is completed. The destruction, death, and injury are caused by the blast wave. Reactive-surround warheads are thin-walled containers filled with combustible aluminum and nitrocellulose. Slurry-explosive warheads are a mixture of a high explosive or other explosive solid mixed with a combustible liquid.

Blast Injuries

Blast explosives kill or injure in three ways: with the blast wave; with flying debris or by collapsing buildings; and by the blast wind throwing bodies against the ground, equipment, structures, and other stationary objects.

According to a 1993 study by the U.S. Defense Intelligence Agency:

The [blast] kill mechanism against living targets is unique--and unpleasant.... What kills is the pressure wave, and more importantly, the subsequent rarefaction [vacuum], which ruptures the lungs.... If the fuel deflagrates but does not detonate, victims will be severely burned and will probably also inhale the burning fuel. Since the most common FAE fuels, ethylene oxide and propylene oxide, are highly toxic, undetonated FAE should prove as lethal to personnel caught within the cloud as most chemical agents.(8)

According to a separate U.S. Central Intelligence Agency study, "the effect of an FAE explosion within confined spaces is immense. Those near the ignition point are obliterated. Those at the fringe are likely to suffer many internal, and thus invisible injuries, including burst eardrums and crushed inner ear organs, severe concussions, ruptured lungs and internal organs, and possibly blindness."(9) Another Defense Intelligence Agency document speculates that because the "shock and pressure waves cause minimal damage to brain tissue...it is possible that victims of FAEs are not rendered unconscious by the blast, but instead suffer for several seconds or minutes while they suffocate."(10)

Lung injuries are particularly difficult to diagnose and treat. If FAEs are used in Chechnya, this would present an additional burden on the ill-equipped and overburdened Chechen hospitals.

1. Interfax, in FBIS, "Federal Troops Use Explosive Gas Bombs in Chechnya," December 27, 1999. This was also reported in Simon Saradzhyan, "Russians face minefields and fierce fire," Sunday Times (London), December 28, 1999 and Daniel Williams, "Assault on Grozny Stalled," Washington Post, December 28, 1999. The source of the information was not identified. Colonel-General Valery Manilov denied media reports Russian forces were using "vacuum bombs." Pavel Korysahkin and Andrey Marychev, ITAR-TASS, in FBIS, "Troops Confront 1,500 Grozny Rebuff," December 28, 1999. According to the Moscow Times, Russian NTV filmed a string of "terrific fireball explosions" in Pigorodnoye, a southeast suburb of Grozny, on December 24, 1999, that appeared "to be the work of TOS-1 [a multiple rocket launcher with fuel-air-explosive-tipped rockets]." Pavel Felgenhauer "Defense Dossier: From Gantamirov to TOS-1," The Moscow Times, December 30, 1999.